Catastrophic events such as Hurricane Katrina and the attacks on the World Trade Center exposed weaknesses in emergency response systems. The primary lesson learned from these disasters is the need for a central command to know exactly where police, fire, and other first-responder personnel are located. Current emergency service agencies have access to systems to track and locate vehicles; however, these agencies lack the ability to rapidly locate an individual.
Many solutions to the problem of rapidly locating personnel have been proposed, including GPS systems, cell phone-based systems, and radio relay systems. Each of these solutions has significant limitations. Vehicle tracking systems use GPS technology with radio transmitters to geo-locate and report the position of a vehicle. In most instances, the problem is two-dimensional, wherein a vehicle is assumed to be ground level and the system needs only solve for latitude and longitude. However, in metropolitan areas, the problem is frequently three-dimensional. For example, personnel can be above ground-level in a building or below ground-level in subways, underground parking garages, mines, etc. Commercially available GPS are simply not accurate enough to precisely locate personnel in high rise buildings, and GPS signals do not reach deep under ground in subways, underground parking garages, mines, etc.
Cell phones have also been proposed as a solution for locating personnel and many cell phone manufacturers are adding GPS to their phone for this purpose. However, by incorporating GPS, this proposed solution suffers from the same limitations of any GPS solution. In addition, cell phones also suffer from signal loss or interference such as when located within buildings or when located underground (e.g., in subways). After Hurricane Katrina, much of the communication and power networks were knocked out by the storm, including many cell towers. Katrina taught us that emergency systems should be completely autonomous, such that emergency systems should not depend on cell phones or electricity from a power grid. Emergency agencies, therefore, cannot depend on cell phones as the primary means of locating personnel.